I need to install a dehumidifier in my basement, as it's musty smelling and some things in storage are getting mildew etc... I don't have a sink downstairs, but do have a 16" hole in the floor in the corner of the slab, it's new construction, 5 yrs old. When I bought the house, it tested a bit high for radon, so the former homeowner (seller) had a radon mitigation system installed. This consisted of covering up the aforementioned 16" diam. hole, and installing 4" pvc duct to an exterior fan which moves the air from the hole outside and up the side of the house to the second floor where it escapes. Note: there's no water in the basement, and it's never been wet...just humid, esp. this summer in upstate NY when we had a lot of rain.

Q: I want to install a dehumidifier that I won't have to physically empty by carrying the water upstairs to dump. I know there are models available that offer a drainage hose out the back. Can I cut a hole in the plastic cover to the radon system and drain there? The volume of water won't be that great, but last thing I want to do is flood the basement.

Option 2: about 3 feet off the floor of the basement is a 4" pvc trap that drains all waste water out of the house into the septic tank out back. I could theoretically put the dehumidifier on a shelf and drain slightly downhill to the trap, as it has a pcv clean-out which sits vertically that I could step down to accept a garden hose. I'm just concerned this might back up...

I would definately agree with Jack. You don't want to drain it into the hole in your floor...those dehumidifiers put out a lot of water...you would be shocked as to how much in a humid basement...a few years ago, (although this was in Atlanta, GA, where the summers are hot and humid) mine was putting out about 5-7 gallons a day down there (a 60-pint unit). I originally had it emptying into a 39 gallon trash can, but got tired of emptying it. I ended up going with the solution Jack suggests.

You also probably don't want this unnecessary volume of water going into your septic system either.

I like Jack's reply, and it would be a fair charge at an environmentally useful alternative. Save the water in a barrel and use it for gardening or watering the lawn. Create a water effect or, my personal favorite, create a personal trout stream. (Just thought about a lot, never actually did it)

As to the hole in your floor? Never, never, never touch a radon mitigation system, particularly in the manner as you mentioned. What you would be doing is creating an amazingly successful system for redistributing radon throughout your neighborhood and your local water supply and defeating the entire purpose of a mitigation system. And,you'd be risking serious repercussions from your local authorities if anyone ever found out. Radon is one of things that, while it can't be seen or smelled, it's serious and shouldn't be tampered with. It effects not only you and your family, but your entire community.